- M939 Truck
The M939 series 5-ton 6x6 truck is a family of
United States Army logistical transportationTruck s which was designed in the late 1980s and has been in service ever since. About 32,000 M939 series trucks are in service. The M939 series is an improved version of the olderM809 Truck series of trucks.pecifications
All models of the M939 share a common basic chassis, motors, etc. The basic truck is a 6x6 (three axles, six sets of tires, all six powered) medium truck. The vehicles have a wide variety of configurations and weights. [ [https://www.logsa.army.mil/etms/data/A/051550.pdf TECHNICAL MANUAL OPERATOR’S MANUAL FOR TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)] , US Army TM 9-2320-272-10, Accessed 2006-05-04]
Note that the motor and tire specifications, along with other improvements, apply to the A2 versions (and A1 versions) of each base model listed below. There is an M928, an M928A1, and M928A2.
Engine
The M939 and M939A1 models use a
Cummins NHC 250 diesel engine, producing 250 hp.(685 ft·lbf@1500 rpm). The M939A2 models use a smaller Cummins 6CTA8.3 engine producing 240 hp.(745 ft·lbf@1500 rpm). All models have the same automatic transmission.Tires
The M939 uses 11:00 R20 tires with two tires per side per axle in the rear (rear tandem duals). The M939A1 and M939A2 series use oversized 14:00 R20 tires and rear tandem singles. M939A2 series vehicles use a centralized tire inflation system.
Models
The M939 series includes the following base models:
afety
The safety of the M939 series of trucks has been criticised, especially braking performance and stability when loaded. In 1999 the US Army began refitting
anti-lock brake systems to the M939 trucks. Until the trucks are modified, they are limited to a 40 mph (65 km/h) top speed by an Army-wide safety order.Prior to that improvement, 26% of all Army vehicle accidents and 53% of all Army vehicle accident fatalities were in M939 series trucks. From 1987 to 1998 the series made up 9% of the total US Army vehicle inventory, but accounted for 34% of all fatal accidents. [ [http://www.globalsecurity.org/military/systems/ground/m939.htm M939 series information page at globalsecurity.org] , Accessed 2006-05-04]
ee also
*
Medium Tactical Vehicle Replacement
*Heavy Expanded Mobility Tactical Truck
*High Mobility Multipurpose Wheeled Vehicle
*Family of Medium Tactical Vehicles References
External links
* [http://www.globalsecurity.org/military/systems/ground/m939.htm M939 series info page at globalsecurity.org]
* [http://www.globalsecurity.org/military/library/report/gao/nsiad-99-082.htm Military Safety: Army M939 5-Ton Truck Accident History and Planned Modifications (Letter Report, 04/09/99, GAO/NSIAD-99-82).]
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